1. Field of the Invention
This invention relates to a filter for use in a storm sewer catch basin. More specifically, the instant invention relates to a filter bag for use in a storm sewer catch basin in which the filter bag and the structure supporting it remains below grade level.
2. Description of the Prior Art
Run off water from rains and the melting of snow is primarily handled by storm sewer systems in most cities. Such storm sewer systems are designed to handle a large quantity of water flowing through them in a short amount of time. In such storm sewer systems, the run off water flows into a grating which is located at grade level, or at the street level, and into a catch basin. The water then flows from the catch basin into an underground storm sewer line.
Often at construction sites, and in many other circumstances where the run off water contains silt or other solid materials and debris, the storm sewer may easily get clogged with silt or other debris. Thus, in order to prevent the water entering the storm sewer line from containing silt or other particulate matter, catch basin filters have been used which include a filter bag suspended from the grating on top of the catch basin. Such a device may be found in U.S. Pat. Nos. 5,372,714 and 5,575,925. In the apparatuses used in the above-mentioned patents, the removable filter bag is supported below grade level in the catch basin and has looped flaps which extend above the grade level. The filter bag is held in place in the basin by the heavy grate which rests on the flaps. The flaps extend above grade level and away from the grate. When the filter bag is to be removed, bars are inserted along the flaps which extend above grade level. Then the filter is lifted by the inserted bars and removed for dumping. This device is illustrated in FIG. 10.
A problem with the above filter arrangement is that in cities located in colder climates, in which snow plows are often needed to clear the streets of snow and ice, the looped flaps which extend above the grate can easily be damaged by such road clearing equipment. Accordingly, there is a need for a catch basin filter which is completely below grade level, in other words, in which not even looped flaps extend above the catch basin grating.